Re: [PATCH][2.6] WARN_ON_STACK_VAR aka fighting variable lifetime bugs

[Zwane Mwaikambo <zwane@arm.linux.org.uk>]

This patch adds some elevator checks for stack variables, there are 
in fact some in theory in the ide_do_drive_cmd path when the caller passes
args via rq->special as a stack variable and does not call with ide_wait*. 

Index: linux-2.6-wli/drivers/block/elevator.c
===================================================================
RCS file: /home/cvs/linux-2.5/drivers/block/elevator.c,v
retrieving revision 1.48
diff -u -p -B -r1.48 elevator.c
--- linux-2.6-wli/drivers/block/elevator.c	27 Jul 2003 01:42:20 -0000	1.48
+++ linux-2.6-wli/drivers/block/elevator.c	9 Aug 2003 18:16:09 -0000
@@ -230,6 +230,11 @@ void __elv_add_request(request_queue_t *
 {
 	struct list_head *insert = &q->queue_head;
 
+	if (!rq->waiting) {
+		WARN_ON_STACK_VAR(rq);
+		WARN_ON_STACK_VAR(rq->special);
+	}
+
 	if (at_end)
 		insert = insert->prev;
 	if (plug)